Conventionally, a discharge lamp in which discharge emission occurs in a discharge gas such as heavy hydrogen and light is emitted is known (for example, see Patent Literatures 1 to 4). For example, an electrodeless discharge lamp including a discharge container of which an internal space is filled with heavy hydrogen, a pair of electrodes attached to an outer surface of the discharge container to face each other across the internal space, and a diaphragm member that limits a portion through which electrons pass in the internal space is described in Patent Literature 1. An opening through which light passes is provided in the electrode that is an anode. In this electrodeless discharge lamp, induction discharge occurs in the internal space when a high-frequency current is supplied between the pair of electrodes. When the discharge converges in the diaphragm body, point-shaped light is generated and emitted from the opening of the anode.